Back now from vacation, and while I was away several people sent me links to point out that string theory promoters definitely aren’t taking a vacation. Links here with a few quick comments, followed by something about the issue of making fun of string theorists.
- Lenny Susskind has a quite good new book out about classical mechanics (see here), but the Economist doesn’t want to talk to him about this, instead it’s the usual string theory promotional effort:
These extra dimensions can be arranged and put together in many different patterns, in a variety of different ways. Not billions, trillions or quintillions of ways, but many more than that. The ways these dimensions are put together into these tiny little spaces determine how particles will behave, what particles will exist, what the constants of nature are—quantities like dark energy or the electric charge of an electron. In string theory all those things are features of the ways that these tiny dimensions are put together. The tiny dimensions are like the DNA of the universe.
- Last month Cumrun Vafa was in Bangalore, explaining (see here, slides here) among other things about the significance of the web of string dualities that makes up M-theory:
String dualities [are] in my opinion perhaps the most fundamental discovery that physicists have made in a century.
Note that the past century includes General Relativity (barely), quantum mechanics, gauge theory, the Standard Model, as well as quite a few discoveries in other areas of physics.
- The Strings 2013 conference included the usual public talks promoting string theory. Witten’s was String Theory and the Universe, which was pretty much unchanged (minus optimism about SUSY at the LHC) from similar talks he has been giving for nearly 20 years (since 1995 and the M-theory proposal). Linde’s was Universe or Multiverse?, about the “new scientific paradigm” of Multiverse Mania. He argues that the virtue of this is that it is “impossible to disprove”.
- David Gross’s public talk on The Frontiers of Particle Physics had nothing to do with string theory, focusing on explaining the standard model and some of the questions it leaves unanswered. Much more interesting was his outlook talk at the conference which included the usual exhortations about string theory being alive and healthy, flourishing with many new and brilliant string theorists, but also included some material unusual in such a venue and much more challenging for his audience. His reference to connections between string theory and condensed matter physics described this as having been “overhyped by our community”. About AdS/CFT, he noted that it “does not provide a satisfactory non-perturbative quantum gravity”.
He commented on the lack of connection between the talks and HEP physics, saying that it was “important that string theorists not retreat into quantum gravity”. About SUSY, he characterized it as “still alive, but not kicking”, and he argued that the LHC results of the past year have made more likely the “Extremely pessimistic scenario” of an SM Higgs, no SUSY, no dark matter, no indication of the next energy threshold. Since “HEP is where string theory connects to reality”, he made the point to the audience that “if this scenario materializes we are all going to suffer.”
I’m not sure why he picked this date, but he encouraged those with post-1999 Ph.D.s to realize that it was now quite possible that those who came before them had “somehow got it wrong”. This was the first time I’ve seen an influential member of the string theory community raise this possibility and call for people to consider it seriously.
- Sean Carroll deals here with arguments from the “Popperazi” that the string theory anthropic multiverse is pseudo-science by ignoring the serious arguments being made. He has his own definition of what science is, which looks to me to open far more questions than it answers. About string theory unification itself, the question has never been whether it’s science, but whether it’s an idea worth pursuing given the ways in which it has so far failed. The best argument for continued pursuit of the idea is of course that there aren’t obviously better ones around, but this raises its own issues.
Sabine Hossenfelder has a posting about an introduction to a Lawrence Krauss talk where the joke was made that “String theorists have to sit in the back”. The context for this was a controversy about the place of women at a discussion involving Krauss hosted by an Islamic group. Like Sabine, I don’t want to discuss here that controversy, just agree there’s a good case to be made that it’s no joking matter. I think she makes a mistake by interpreting the joke as an attack on string theorists (it’s a joke, after all, open to many interpretations), but I was struck by her perception of string theorists as an embattled minority under unfair attack, as well as the claim that it’s not all right to in any way make fun of them.
The situation these days is clearly very different than it was back in 2004 when I started this blog, partly because of the past decade of failure of string theory unification to get anywhere, partly because of the negative LHC results, partly because of the multiverse, and partly because of the public behavior of some in the string theory community in reaction to criticism. Given the high profile ongoing promotional campaign exemplified above, I don’t think we’re yet at the point where criticism of string theorists is “kicking them when they’re down”, and humor is sometimes the best way to make a point concisely. Probably the most incisive criticism of string theory ever made was made in a cartoon, and personally I’ve never understood how it is even possible to take arguments like Linde’s seriously (and am not even sure he does…), so I see a role for humor in charting the continuing story of the collapse of the heavily influential string theory unification paradigm.
Update: If you noticed more than the usual sloppiness, incompleteness and incoherence, maybe it was because this got published early, while I was in the middle of writing it.
The multiverse is the only known explanation so in a sense it has already been tested
Is it all right to make fun of this, or should one seriously discuss the scientific merits here?